This work contains the results of research on centrifugal enrichment of 1 1 8 Sn isotope followed by irradiation and, finally, a second centrifugal enrichment to produce high specific activity 1 1 9 m Sn. Non-steady-state separation methods were used for the effective extraction of the radionuclide 1 1 9 m Sn from the irradiated target. As a result of this work, radiation sources based on 1 1 9 m Sn were obtained with a specific activity of 500mCi/g. This is 100 times greater than the specific activity obtained after irradiation in the reactor alone. In addition, the sources had an previously unattainable radio-purity ratio of 1 1 3 Sn/ 1 1 9 m Sn of approximately 10 - 6 .